Flip chip light emitting diode with micromesas and a conductive mesh

ABSTRACT

A flip chip light emitting diode ( 12 ) includes a light-transmissive substrate ( 10 ) with a base semiconducting layer ( 40 ) disposed thereupon. A conductive mesh ( 18 ) is disposed on the base semiconducting layer ( 40 ) and is in electrically conductive contact therewith. Light-emitting micromesas ( 30 ) are disposed in openings ( 20 ) of the conductive mesh ( 18 ). Each light emitting micromesa ( 30 ) has a topmost layer ( 46 ) of a second conductivity type that is opposite the first conductivity type. A first conductivity type electrode ( 14 ) is disposed on the base semiconducting layer ( 40 ) and is in electrical communication with the electrically conductive mesh ( 18 ). An insulating layer ( 60 ) is disposed over the electrically conductive mesh ( 18 ). A second conductivity type electrode layer ( 24 ) is disposed over the insulating layer ( 60 ) and the light-emitting micromesas ( 30 ). the insulating layer ( 60 ) insulates the second conductivity type electrode layer ( 24 ) from the electrically conductive mesh ( 18 ).

BACKGROUND

The present invention relates to the lighting arts. It is especiallyrelated to gallium nitride-based high power flip chip light emittingdiodes for lighting applications, and will be described with particularreference thereto. However, the invention will also find application inconjunction with other light emitting diode applications, other types oflight emitting diodes, and other types of semiconductor light emitterssuch as vertical cavity surface emitting lasers.

Light emitting diodes are increasingly being employed in outdoordisplays and signals, indoor illumination, and other applications thatcall for high levels of light output. Many of these applications employgallium nitride-based light emitting diodes that emit light in the blueto near ultraviolet range. For lighting applications, a suitablephosphor is typically applied as a die coating or is integrated into adie-sealing encapsulant to convert the blue or ultraviolet lightemitting diode output to a white or other selected light. The poweroutput of such light emitting diodes is determined by a number offactors, including: light extraction from the semiconductor die; lateralcurrent uniformity across the die; and the effectiveness of die heatsinking.

In a flip chip arrangement, active light-generating layers are depositedon a light-transmissive substrate wafer, and frontside electrodes areformed on the light generating layers. The substrate wafer is diced, andeach die is bonded to contact pads of a sub-mount, printed circuit boardor other support in flipped orientation, that is, with the lightgenerating layers proximate to the support and the substrate distal fromthe support. In the flip chip arrangement, light is extracted throughthe light-transmissive substrate. However, problems can arise in thatwave guiding in the light-generating layers tends to trap light andreduce the light extraction efficiency. Moreover, uniformity of lateralcurrent spreading across the active device area suffers because then-type and p-type electrodes are non-overlapping. Heat sinking is alsolimited and asymmetric between the p-type and n-type electrodes.

The present invention contemplates an improved apparatus and method thatovercomes the above-mentioned limitations and others.

BRIEF SUMMARY

According to one aspect, a flip chip light emitting diode is disclosed,including a light-transmissive substrate. A base semiconducting layer ofa first conductivity type is disposed on the light-transmissivesubstrate. A conductive mesh is disposed on the base semiconductinglayer and is in electrically conductive contact therewith.Light-emitting micromesas are disposed in openings of the conductivemesh. Each light emitting micromesa has a topmost layer of a secondconductivity type that is opposite the first conductivity type. A firstconductivity type electrode is disposed on the base semiconducting layerand is in electrical communication with the electrically conductivemesh. An insulating layer is disposed over the electrically conductivemesh. A second conductivity type electrode layer is disposed over theinsulating layer and the light-emitting micromesas. the insulating layerinsulates the second conductivity type electrode layer from theelectrically conductive mesh.

According to another aspect, a flip chip light emitting diode isdisclosed, including a light-transmissive substrate. A basesemiconducting layer of a first conductivity type is disposed on thelight-transmissive substrate. Light-emitting micromesas are disposed onthe base semiconducting layer. A first conductivity type electrode isdisposed on the base semiconducting layer. The first conductivity typeelectrode includes a bonding pad region and at least one conductivefinger extending from the bonding pad region to effect electricalcommunication between the first conductivity type electrode and thelight-emitting micromesas. An insulating layer is disposed over the basesemiconducting layer and the at least one conductive finger of the firstconductivity type electrode. The insulating layer has openings to exposethe bonding pad region of the first conductivity type electrode andtopmost portions of the micromesas. A second conductivity type electrodelayer is disposed over the insulating layer and the light-emittingmicromesas. The insulating layer insulates the second conductivity typeelectrode layer from the at least one conductive finger of the firstconductivity type electrode and the base semiconducting layer.

According to yet another aspect, a flip chip light emitting diode isdisclosed, including a light transmissive substrate. A basesemiconducting layer is disposed on the light transmissive substrate.Light emissive micromesas are arranged on the base semiconducting layer.the light emissive micromesas define an active area of the lightemitting diode. A continuous electrode layer is disposed over the activearea and contacts the tops of the micromesas. The continuous electrodelayer is substantially co-extensive with the active area of the lightemitting diode. An electrically conductive mesh is deposited on the basesemiconducting layer in trenches between the micromesas. Theelectrically conductive mesh defines a continuous electrode that issubstantially co-extensive with the active area of the light emittingdiode. A discrete electrode is disposed outside of the active area ofthe light emitting diode. The discrete electrode electricallycommunicates with the conductive mesh.

Numerous advantages and benefits of the present invention will becomeapparent to those of ordinary skill in the art upon reading andunderstanding the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may take form in various components and arrangements ofcomponents, and in various process operations and arrangements ofprocess operations. The drawings are only for purposes of illustratingpreferred embodiments and are not to be construed as limiting theinvention. In the FIGURES, layer thicknesses and device lateraldimensions are not drawn to scale.

FIG. 1 shows a top view of a fabrication wafer with light emitting diodedevices formed thereon, before dicing of the wafer. In depicting thelight emitting diode devices in FIG. 1, the p-type electrode is omittedto show the spiral electrode fingers.

FIG. 2 shows a top view of one of the light emitting diode die afterdicing of the fabrication wafer of FIG. 1. Again, depiction of thep-type electrode is omitted in FIG. 2 to show underlying features, andthe extent of the p-type electrode is indicated by dashed lines.

FIG. 3 shows a top view of two openings defined by the conductive meshof the light emitting diode die of FIG. 2, along with micromesasdisposed in the mesh openings. Again, the p-type electrode is notdepicted in FIG. 3 so as to show underlying features.

FIG. 4 shows the cross-section S-S indicated in FIG. 3.

FIG. 5 shows an exemplary strip sub-mount onto which the light emittingdiode dice such as the die shown in FIG. 2 are suitably flip chipbonded.

FIG. 6 shows, for an alternative embodiment, a top view of two openingsdefined by the conductive mesh of the light emitting diode die, alongwith micromesas disposed in the mesh openings In the alternateembodiment of FIG. 6, the electrode finger forms part of the conductivemesh.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIG. 1, a fabrication wafer 10 has disposed thereon aplurality of light emitting diode dice 12. The fabrication wafer 10 issilicon carbide (SiC), sapphire (Al₂O₃), gallium phosphide (GaP),gallium nitride (GaN), or another crystalline substrate suitable fordepositing group III-nitride epitaxial semiconductor layers. The lightemitting diode dice 12 are preferably fabricated on the fabricationwafer 10, followed by dicing of the wafer 10 to produce separated LEDdice.

With reference to FIG. 2, one such separated light emitting diode die 12is shown, which includes an n-type electrode 14 electrically connectedwith a spiral electrode finger 16. The spiral electrode finger 16provides distribution of electrical current across a lateral area of thelight emitting diode die 12. In FIG. 2, the electrode finger 16 is shownas having a substantially uniform width with increasing distance alongthe finger from the n-type electrode 14. However, the electrode fingeroptionally has a narrowing or tapering width with increasing distancealong the finger from the n-type electrode. Such optional taperingaccounts for a decrease in electrical current magnitude with increasingdistance along the finger from the n-type electrode 14 during deviceoperation. Tapering is commonly used in electrode fingers of solar cellsfor this purpose. Moreover, the electrode finger can have otherconfigurations besides a spiral, or multiple electrode fingers canextend from the n-type electrode 14. The specific configuration of theelectrode finger or fingers is selected to efficiently distributeelectrical current across the lateral area of the light emitting diodedie 12.

To further promote uniform electrical current spreading, a conductivemesh 18 of deposited patterned metal or another conductive materialdefines mesh openings 20. In the illustrated embodiment, the conductivemesh 18 has a rectangular grid configuration with rectangular cellsdefining square mesh openings 20. However, the conductive mesh 18 canhave circular- or otherwise-shaped cells, and can defineotherwise-shaped openings. Moreover, rather than a rectangular symmetry,the conductive mesh can have a hexagonal or other symmetry, or can beaperiodic. A p-type electrode 24 is distributed across the lightemitting diode 12 in generally continuous fashion, excepting that thep-type electrode 24 does not laterally overlap the n-type electrode 14.(The p-type electrode 24 is omitted in FIGS. 1-3 to show underlyingfeatures. In FIG. 2 the lateral extent of the p-type electrode 24 isindicated by dashed lines).

With reference to FIGS. 3 and 4, each mesh opening 20 has fourmicromesas 30 disposed therein. In other words, the micromesas 30 arelaterally surrounded by the conductive mesh 18. The micromesas 30 aredistributed across an active device area of the light emitting diode die12. In other words, the distribution of the micromesas 30 effectivelydefines the active area of the light emitting diode die 12. Theconductive mesh 18 can be viewed as a continuous n-type electrodedisposed over the active area of the light emitting diode die 12 andsubstantially co-extensive with the active area. The continuouselectrode defined by the conductive mesh 18 is in electricalcommunication with the discrete n-type electrode 14. The discrete n-typeelectrode 14 is disposed outside of the active area. The p-typeelectrode 24 is also substantially co-extensive with the active area ofthe light emitting diode die 12.

As seen in the cross-section S-S shown in FIG. 4, each micromesa 30 hasslanted sidewalls 32 that define trenches 34 surrounding the micromesas30. Although four micromesas 30 are enclosed within each mesh opening 20in the illustrated embodiment, more or fewer micromesas can be enclosedwithin each conductive mesh opening. Indeed, as few as a singlemicromesa per mesh opening can be enclosed. The deposited metal or otherconductive material defining the conductive mesh 18 is disposed in atleast some of the trenches 34.

With particular reference to FIG. 4, which shows a cross-section of twomicromesas 30 and the surrounding conductive mesh 18, in a preferredembodiment a base semiconducting layer 40 is deposited on the substrate10. For a p-on-n diode configuration, the base semiconducting layer 40is doped n-type, and in a preferred group III-nitride embodiment ispreferably gallium nitride (GaN). An active layer 42, which ispreferably an indium gallium nitride (In_(x)Ga_(1-x)N) alloy layer(where x is the molar fraction of indium nitride (InN)), is disposed onthe base semiconducting layer 40. A p-type region is disposed on theactive layer 42. In the illustrated embodiment the p-type regionincludes an aluminum gallium nitride (Al_(y)Ga_(1-y)N) alloy layer 44(where y is the molar fraction of aluminum nitride (AlN)) on top ofwhich is deposited a topmost p-type gallium nitride (GaN) layer 46.

The semiconductor layers 40, 42, 44, 46 are preferably deposited on thefabrication substrate wafer 10 by metalorganic chemical vapor deposition(MOCVD; also known in the art as organometallic vapor phase epitaxy,OMVPE, and other similar nomenclatures), by molecular beam epitaxy(MBE), chemical beam epitaxy (CBE), or another epitaxial depositiontechnique.

The semiconductor layers 40, 42, 44, 46 define an exemplary lightemitting diode device structure. Those skilled in the art can readilymodify the exemplary diode structure to suit specific applications. Forexample, the base semiconducting layer 40 is shown in FIG. 4 as beingdeposited directly onto the substrate 10. However, optionally anepitaxy-promoting layer of aluminum nitride (AlN) or another material isdeposited first to improve the subsequent epitaxy. An n-on-p structurecan be substituted for the illustrated p-on-n device structure. Theactive layer can include multiple quantum wells, a superlattice, oranother multiple-layer structure that promotes radiative recombinationof electron-hole pairs. Moreover, the exemplary group III-nitride devicestructure can be replaced by a device structure of a groupIII-phosphide, group III-arsenide, or other material system, or by acombination of such material systems. For example, layers oflattice-matched compositions of group III-arsenide and groupIII-phosphide compounds can be combined in a diode structure.

After epitaxial deposition, the micromesas 30 are formed by mesa etchingto define the slanted sidewalls 32 and the trenches 34. The mesa etchingcan employ dry etching such as plasma etching, reactive ion beametching, or the like, wet etching, or the like. Preferably, themicromesas 30 are square-shaped with dimensions of about 3 microns to 20microns on a side (corresponding to micromesa areas between about 9square microns and about 400 square microns). However, other micromesashapes and sizes can be used. The angle of the slanted sidewalls 32 isselected to optimize light extraction efficiency and active area. Largerslant angles (that is, sides that deviate significantly from vertical)promote higher light extraction efficiency in the finished flip-chipdevice, since the slanted sides act as mirrors that reflect laterallydirected light 50 generally toward the transparent substrate 10.However, larger slant angles also reduce the micromesa-to-trench arearatio, which reduces active device area. The angle of the slantedsidewalls 32 is optimized for specific light emitting deviceapplications based on these considerations.

With reference to FIG. 4, it will be observed that the mesa etching doesnot completely remove the base semiconducting layer 40. That is, atleast a portion of the base semiconducting layer 40 remains in the areaof the trenches 34, and so the base semiconducting layer 40 iscontinuous across the active device area. This lateral continuity of thebase semiconducting layer 40 enhances current spreading amongst themicromesas 30.

The conductive mesh 18 is deposited and patterned on the basesemiconducting layer 40 within selected trenches 34. In one suitableembodiment, a lift-off patterning is employed, in which resist isapplied and patterned to expose areas where the mesh 18 is to bepresent. The conductive mesh metal is deposited by vacuum evaporation oranother technique, and the metal coats both the exposed areas and theresist. The resist is then stripped using a suitable solvent to lift offthe metal except in the exposed areas. In another approach, the meshmetal is deposited first, followed by resist deposition and patterningto expose the metal in areas other than where the mesh 18 is to bepresent. A suitable wet chemical etchant or dry etching is applied toremove the exposed metal, followed by stripping of the resist. In yetanother suitable approach, a shadow mask is used to directly pattern themetal during deposition.

Preferably, the n-type electrode 14 and the electrode finger 16 areformed along with the conductive mesh 18. However, if the n-typeelectrode 14 and/or the electrode finger 16 have a greater thicknessthan the mesh 18, are made of a different metal, or are otherwisematerially different from the mesh 18, then separate fabricationprocesses are suitably used for producing the conductive mesh 18, theelectrode finger 16, and the n-type electrode 14.

After metal deposition, an insulator 60 is applied over at least themetal mesh 18, and preferably also over the electrode finger 16 and thesidewalls 32 of the micromesas 30. The insulating film 60 includesopenings through which the topmost p-type layer 46 is at least partiallyexposed. The openings in the insulator film 60 are produced usinglithography, shadow masking during insulator deposition, or anothersuitable patterning process. Deposition of the insulator 60 is followedby a blanket p-type contact metal deposition that forms the p-typeelectrode layer 24. The p-type electrode layer 24 contacts the exposedportion of the topmost p-type layer 46 of each micromesa 30 to makeelectrical contact therewith. However, the insulator 60 electricallyisolates the p-type electrode layer 24 from the conductive mesh 18.Moreover, the deposition of the p-type electrode layer 24 is shadowmasked or performed in conjunction with lithography to keep the p-typeelectrode layer 24 separate from the n-type electrode 14.

Preferably, the fabrication processes discussed above, up to andincluding deposition of the p-type electrode layer 24, are performed aswafer-level processes to define the processed wafer shown in FIG. 1.After deposition of the p-type electrode layer 24, the wafer is diced toseparate each light emitting diode device die 12. The individual devicedie have exposed electrodes 14, 24 that are then flip-chip bonded to asub-mount, printed circuit board, or other support that has bonding padsaligned with the electrodes 14, 24.

FIG. 5 shows a portion of an exemplary strip-type sub-mount 70. Theillustrated portion includes six bonding pad sets 72 for bonding sixlight emitting diode dice 12. Each bonding pad set 72 includes an n-typebonding pad 74 that bonds with the n-type electrode 14, and a p-typebonding pad 76 that bonds with the p-type electrode 24. The exemplarystrip sub-mount 70 has two positive electrical power buses 80 and twonegative electrical power buses 82 that interconnect the bonding padsets 72. The strip-type sub-mount 70 is exemplary only. Those skilled inthe art can readily construct other sub-mounts, printed circuit boardlayouts, or the like for specific applications.

In operation, the electrodes 14, 24 receive electrical power from thebonding pads 74, 76. Current communicates with the topmost p-type layer46 through the p-type electrode 24, which distributes current amongstthe micromesas 30. Similarly, the micromesas 30 are in electricalcommunication with the n-type electrode 14 via the electrode finger 16and the base semiconducting layer 40. The conductive mesh 18 providesfurther current spreading to distribute current amongst the micromesas30. Electrical communication between the electrode finger 16 and theconductive mesh 18 is via the base semiconducting layer 40, since thereis no direct electrical contact between the electrode finger 16 and theconductive mesh 18.

An additional benefit of the conductive mesh 18 and the electrode finger16 is improved thermal heat sinking. If the conductive mesh 18 and theelectrode finger 16 are made of thermally conductive materials, such asmost metals, then they provide heat sinking paths that conduct heatgenerally toward the n-type electrode 14. These heat sinking paths aremore efficient than conducting heat from the buried n-type layer 40through the active layer 42 and the p-type region 44, 46 to the p-typeelectrode 24, and the improved heat removal from deeply buried layers ofthe epitaxial structure can reduce heating in the active region of thedevice.

With reference to FIG. 6, a variant embodiment is shown, which includesa conductive mesh 18′ defining mesh openings 20′, and micromesas 30′defined by trenches 34′. These features are substantially similar tocorresponding features of the embodiment of FIGS. 1-4, and thecorrespondence is indicated by using corresponding primed referencenumbers in FIG. 6. The embodiment of FIG. 6 differs from that of FIGS.1-4 in that the electrode finger 16′ is in direct electrical contactwith the conductive mesh 18′. In other words, the electrode finger 16′forms part of the conductive mesh 18′. This is in contrast to theembodiment of FIGS. 1-4, in which electrical communication between theelectrode finger 16 and the conductive mesh 18 is via the basesemiconducting layer 40. The embodiment of FIG. 6 may be preferred indevices where the base semiconducting layer has relatively lowconductivity. In such devices, direct electrical contact between theelectrode finger 16′ and the conductive mesh 18′ can reduce seriesresistance of the device. On the other hand, for a relatively highconductivity base semiconducting layer, the indirect electricalcommunication between the electrode finger 16 and the conductive mesh 18of the embodiment of FIGS. 1-4 can promote more uniform currentspreading. For a sufficiently conductive base semiconducting layer, theconductive mesh 18 is optionally omitted and current spreading isaccomplished through the electrode finger and the base semiconductinglayer 40.

The described embodiments optionally incorporate a phosphor in variousways. In one approach, the light transmissive substrate 10 contains aphosphor doping. In another approach, a phosphor coating is applied to aside of the substrate 10 opposite from the side of the substrate onwhich the semiconducting layers 40, 42, 44, 46 are disposed. In yetanother approach, an epoxy or other encapsulant is used to encapsulatethe light emitting diode die 12 after flip chip bonding to the sub-mount70, and the epoxy or other encapsulant contains a phosphor. Thoseskilled in the art can readily incorporate a phosphor or a plurality ofphosphors using these or other similar approaches. Such a phosphor orphosphors can be used, for example, to convert blue or ultravioletradiation produced by group III-nitride-based micromesas 30 intogenerally white light.

The invention has been described with reference to the preferredembodiments. Obviously, modifications and alterations will occur toothers upon reading and understanding the preceding detaileddescription. It is intended that the invention be construed as includingall such modifications and alterations insofar as they come within thescope of the appended claims or the equivalents thereof.

1. A flip chip light emitting diode including: a light-transmissivesubstrate; a base semiconducting layer of a first conductivity typedisposed on the light-transmissive substrate; a conductive mesh disposedon the base semiconducting layer and in electrically conductive contacttherewith; light-emitting micromesas disposed in openings of theconductive mesh, each light emitting micromesa having a topmost layer ofa second conductivity type that is opposite the first conductivity type;a first conductivity type electrode disposed on the base semiconductinglayer and in electrical communication with the electrically conductivemesh; an insulating layer disposed over the electrically conductivemesh; and a second conductivity type electrode layer disposed over theinsulating layer and the light-emitting micromesas, the insulating layerinsulating the second conductivity type electrode layer from theelectrically conductive mesh.
 2. The flip chip light emitting diode asset forth in claim 1, further including: at least one conductive fingerdisposed on the base semiconducting layer, the at least one conductivefinger effecting the electrical communication between the firstconductivity type electrode and the conductive mesh.
 3. The flip chiplight emitting diode as set forth in claim 2, wherein the at least oneconductive finger contacts the first conductivity type electrode butdoes not contact the conductive mesh, the electrical communication beingeffected by electrical current flow between the at least one conductivefinger and the conductive mesh passing through the base semiconductinglayer.
 4. The flip chip light emitting diode as set forth in claim 1,wherein the base semiconducting layer and the topmost layer are formedof group III-nitride materials.
 5. The flip chip light emitting diode asset forth in claim 4, wherein the first conductivity type is n-type, andthe second conductivity type is p-type.
 6. The flip chip light emittingdiode as set forth in claim 1, wherein the micromesas are square-shapedwith dimensions of about three to twenty microns on a side.
 7. The flipchip light emitting diode as set forth in claim 1, wherein theconductive mesh includes a rectangular grid.
 8. The flip chip lightemitting diode as set forth in claim 1, wherein at least two micromesasare disposed in each opening of the conductive mesh.
 9. The flip chiplight emitting diode as set forth in claim 1, wherein four micromesasare disposed in each opening of the conductive mesh.
 10. The flip chiplight emitting diode as set forth in claim 1, wherein micromesas eachinclude: slanted sidewalls arranged to reflect laterally directed lightgenerally toward the light-transmissive substrate.
 11. A flip chip lightemitting diode including: a light-transmissive substrate; a basesemiconducting layer of a first conductivity type disposed on thelight-transmissive substrate; light-emitting micromesas disposed on thebase semiconducting layer; a first conductivity type electrode disposedon the base semiconducting layer, the first conductivity type electrodeincluding a bonding pad region and at least one conductive fingerextending from the bonding pad region to effect electrical communicationbetween the first conductivity type electrode and the light-emittingmicromesas; an insulating layer disposed over the base semiconductinglayer and the at least one conductive finger of the first conductivitytype electrode, the insulating layer having openings to expose thebonding pad region of the first conductivity type electrode and topmostportions of the micromesas; and a second conductivity type electrodelayer disposed over the insulating layer and the light-emittingmicromesas, the insulating layer insulating the second conductivity typeelectrode layer from the at least one conductive finger of the firstconductivity type electrode and the base semiconducting layer.
 12. Theflip chip light emitting diode as set forth in claim 11, wherein themicromesas have non-vertical sidewalls inclined at an angle selected toreflect light produced in the micromesas toward the light-transmissivesubstrate.
 13. The flip chip light emitting diode as set forth in claim11, wherein the micromesas have a lateral area between 9 square micronsand 400 square microns.
 14. The flip chip light emitting diode as setforth in claim 13, wherein the micromesas have a generally squarelateral shape.
 15. The flip chip light emitting diode as set forth inclaim 11, wherein the micromesas electrically communicate with the atleast one conductive finger of the first conductivity type electrodethrough the base semiconducting layer.
 16. The flip chip light emittingdiode as set forth in claim 11, further including: a conductive meshdisposed on the base semiconducting layer, the micromesas being arrangedin mesh openings defined by the conductive mesh.
 17. The flip chip lightemitting diode as set forth in claim 16, wherein the conductive meshelectrically communicates with the at least one conductive fingerthrough the base semiconducting layer.
 18. The flip chip light emittingdiode as set forth in claim 16, wherein the at least one conductivefinger forms part of the conductive mesh.
 19. The flip chip lightemitting diode as set forth in claim 11, wherein each micromesaincludes: a topmost layer of a second conductivity type, the secondconductivity type being of an opposite conductivity from the firstconductivity type, the second conductivity type electrode layerelectrically contacting the topmost layer.
 20. A flip chip lightemitting diode including: a light transmissive substrate; a basesemiconducting layer disposed on the light transmissive substrate; lightemissive micromesas arranged on the base semiconducting layer, the lightemissive micromesas defining an active area of the light emitting diode;a continuous electrode layer disposed over the active area andcontacting the tops of the micromesas, the continuous electrode layerbeing substantially co-extensive with the active area of the lightemitting diode; an electrically conductive mesh deposited on the basesemiconducting layer in trenches between the micromesas, theelectrically conductive mesh defining a continuous electrode that issubstantially co-extensive with the active area of the light emittingdiode; and a discrete electrode disposed outside of the active area ofthe light emitting diode, the discrete electrode electricallycommunicating with the conductive mesh.
 21. The flip chip light emittingdiode as set forth in claim 20, wherein the discrete electrode and thecontinuous electrode layer are adapted for flip chip bonding to anassociated support.
 22. The flip chip light emitting diode as set forthin claim 20, further including: a conductive finger extending from thediscrete electrode into the active area of the light emitting diode toeffect electrical communication of the discrete electrode with thecontinuous electrode defined by the conductive mesh.
 23. The flip chiplight emitting diode as set forth in claim 20, further including: aninsulating film disposed between the continuous electrode layer and thecontinuous electrode defined by the conductive mesh, the continuouselectrode layer and the continuous electrode defined by the conductivemesh being electrically isolated from one another by the insulatingfilm.